Mono-5-substituted-thio-3-chloro-4H-1,2,6-thiadiazin-4-one antifungal agents

ABSTRACT

Selected mono-5-substituted-thio-3-chloro-4H-1,2,6-thiadiazin-4-ones having the formula ##STR1## wherein X is substituted thio, are described which are useful for control of fungal disease in plants.

BACKGROUND OF THE INVENTION

The present invention relates to a method for controlling fungal diseasein plants, to novel antifungal compositions, and to compounds useful forcontrolling fungi which attack agricultural and garden plants and seeds.More particularly, the invention relates to the use of a selectedmono-5-substituted-3-chloro-4H-1,2,6-thiadiazin-4-one as an antifungalagent for controlling fungal disease in plants.

Geevers and Trompen disclosed the preparation3,5-dichloro-4H-1,2,6-thiadiazin-4-one and its use as an intermediate toprepare various other 5-substituted-3-chloro-4H-1,2,6-thiadiazin-4-onesincluding the 5-phenylthio and 5-methylthio derivative. J. Geevers andW. P. Trompen, Rec. Trav. Chim., 93, 270 (1974). The 5-phenoxyderivatives are disclosed in U.S. Patent Application Ser. No. 728,860filed of even date herewith.

While the 5-phenylthio and 5-methylthio derivatives and the method forpreparing them have been disclosed, the reference provides no indicationof any biological activity. More particularly, there is no suggestionthat the compounds of this invention have antifungal activity.

It has now been found that selected mono-5-substituted3-chloro-4H-1,2,6-thiadiazin-4-ones, which are hereinafter described,exhibit excellent antifungal activity and are useful in providingcontrol of fungal disease in agricultural crops by foliar, seed, andsoil application.

SUMMARY OF THE INVENTION

The present invention thus provides (1) a method for controlling fungaldisease in plants which comprises applying a selectedmono-5-substituted-3-chloro-4H-1,2,6-thiadiazin-4-one, as defined below,to the locus where control is desired, (2) antifungal compositions forcontrol of fungal disease in plants, and (3) certain novel compoundswhich are useful for control of fungi.

DETAILED DESCRIPTION

In accordance with a first aspect of the present invention, there isprovided a method for controlling fungal disease in agricultural cropsand other plants which comprises applying to the locus where control isdesired an effective fungistatic or fungicidal amount of amono-5-substituted-3-chloro-4H-1,2,6-thiadiazin-4-one of the formula##STR2## in which X is alkylthio, phenylthio, phenyl(lower)alkylthio,cycloalkylthio having 5 to 7 ring carbon atoms or substituted phenylthioof the formula ##STR3## in which each R is independently selected fromlower alkyl, lower alkoxyl, lower acylamino, lower alkoxycarbonyl,nitro, cyano or halogen and n is an integer having a value of 1-3.However, when R is lower alkyl or halogen n may have a value of 1 to 5inclusive.

Unless it is otherwise indicated, the term "lower" means having 1 to 6carbon atoms, straight or branched chain, preferably 1 to 4 carbonatoms, the term alkyl means having 1 to 8 carbon atoms, and the term"halogen" means bromine, chlorine and fluorine or iodine, advantageouslybromine, chlorine or fluorine, preferably chlorine or bromine.

In the method of this invention an effective fungistatic or fungicidalamount of active ingredient is applied to foliage or seeds ofagricultural plants or to the soil in which the plants are growing orare to be planted, i.e., the locus where control is desired. When soapplied, the compounds prevent fungal infection or inhibit furtherdevelopment of a preexisting fungal disease.

In the method of this invention the selected antifungal agent may beapplied as the technical material or as a formulated product. Typicalformulations include the antifungal agent in combination with anagriculturally acceptable carrier, preferably with a surface activeagent, and optionally with other active ingredients. Suitableformulations include granules, powders, or liquids, the choice varyingwith the fungus and environmental factors present at the particularlocus of infestation. Thus the compounds may be formulated as granulesof various sizes, as dusts, as wettable powders, as emulsifiableconcentrates, as solutions, as dispersions, as controlled releasecompositions, and the like.

A typical formulation may vary widely in concentration of the activeingredient depending on the particular agent used, the additives andcarriers used, other active ingredients, and the desired mode ofapplication. With due consideration of these factors, the activeingredient of a typical formulation may, for example, be suitablypresent at a concentration of about 0.5% up to about 99.5% by weight ofthe formulation. Additives and carriers may comprise about 99.5% byweight to as low as about 0.5% by weight of the formulation. Surfaceactive agents, if employed in the formulation, may be present at variousconcentrations, suitably in the range of 1% to 30% by weight.

The formulation may be used as such or diluted to a desired use dilutionwith a suitable diluent or carrier. The concentration of the activeingredient in use dilution is normally in the range of about 0.001% toabout 4% by weight. Many variations of spraying, dusting,soil-incorporated, and controlled or slow release compositions in theart may be used by substituting or adding a compound of this inventioninto compositions known or apparent to the art.

The antifungal agents of this invention may be formulated and appliedwith other compatible active ingredients, including nematicides,insecticides, acaricides, other fungicides, plant regulators,herbicides, fertilizers, etc.

In applying the foregoing chemicals, whether alone or with otheragricultural chemicals, an effective inhibitory or fungicidal amount ofthe active ingredient must be applied. While the application rate willvary widely depending on the choice of compound, the formulation andmode of application, the plant species being protected, and the plantingdensity, a suitable use rate may be in the range of 0.05 to 5kg/hectare, preferably 0.5 to about 4 kg/hectare.

The antifungal composition of this invention comprises a compound offormula I as defined above in admixture with an agriculturallyacceptable carrier, preferably containing a compatible surface activeagent.

The novel compounds of this invention are those of Formula I in which Xis other than methylthio or phenylthio; that is, the compounds offormula I in which X is alkylthio of 2 to 8 carbon atoms,phenyl(lower)alkylthio, cycloalkylthio having 5-7 ring carbon atoms orsubstituted phenylthio of the Formula II in which R is lower alkyl,lower alkoxyl, lower acylamino, lower alkoxycarbonyl, nitro, cyano orhalogen and n in an integer having a value of 1 to 3 inclusive, with theproviso that when R is lower alkyl or halogen n may have a value of 1 to5 inclusive.

The compounds of this invention are prepared according to the teachingof Geevers and Trompen, supra; that is, by reaction3,5-dichloro-4H-1,2,6-thiadiazin-4-one with thiolate ions, for example,sodium phenothiolate. The following examples are typical of thepreparation of the compounds.

EXAMPLE I Synthesis of 3,5-Dichloro-4H-1,2,6-thiadiazin-4-one

A 50 ml flask was charged with 20 ml formic acid. The flask was purgedwith a stream of dry nitrogen. The nitrogen purge was continued while6.3 g 3,4,4,5-tetra-chloro-4H-1,2,6-thiadiazinone was added dropwiseover 0.5 hour during which the temperature of the reaction mixture wasmaintained at 10±1° C. Following addition the reaction mixture wasstirred at 10° C for 2 hours then at room temperature for 64 hours, thenpoured into 60 ml. ice-water with stirring. The resulting mixture wasfiltered and the filter cake washed with water and dried to yield 2.2 gof pale yellow 3,5-dichloro-4H-1,2,6-thiadiazin-4-one, mp 81°-82° C.

EXAMPLE II Synthesis of 3-Chloro-5-phenylthio-4H-1,2,6-thiadiazin-4-one

In one portion 2.5 g of trimethylamine was added to a solution of 4.6 gof 3,5-dichloro-4H-1,2,6-thiadiazin-4-one in 75 ml of ethyl ether in a250 ml flask. A solution of 2.8 g of thiophenol in 25 ml of ethyl etherwas then added dropwise to the flask during a 15 minute period. Thereaction was allowed to stir for 3 hrs. after which it was filtered. Thefilter cake was washed with ether, and the filter cake was discarded.Successively, the ether solution was washed twice with 50 ml of waterand once with 50 ml of saturated sodium chloride solution. The ethersolution was then dried over anhydrous sodium sulfate. The ether wasevaporated, leaving a solid residue which was recrystallized from 75 mlof cyclohexane. The yellow-orange3-chloro-5-phenylthio-4H-1,2,6-thiadiazin-4-one weighed 3.6 g, mp99.5°-101.5° C. (Lit. mp 102.5°-103.5° C, J. Geevers and W. P. Trompen,supra.). The ir spectrum was consistent with the assigned structure.

Analyses calc'd for C₉ H₅ ClN₂ OS₂ : C 42.11; H 1.96; N 10.91. Found: C42.39; H 2.07; N 10.94.

The compounds of this invention which are set forth below have beensynthesized in accordance with the typical preparatory method set forthin Examples I and II. An identifying number is provided for eachcompound. This compound number is used below in reporting biologicaldata realting to the compound.

    ______________________________________                                        Compound No.                                                                              Identity                                                          ______________________________________                                        1           3-chloro-5-(methylthio)-                                                      4H-1,2,6-thiadiazin-4-one                                         2           3-chloro-5-(ethylthio)-                                                       4H-1,2,6-thiadiazin-4-one                                         3           3-chloro-5-propylthio-4H-                                                     1,2,6-thiadiazin-4-one                                            4           5-butylthio-3-chloro-4H-                                                      1,2,6-thiadiazin-4-one                                            5           3-chloro-5-pentylthio-4H-                                                     1,2,6-thiadiazin-4-one                                            6           3-chloro-5-(phenylthio)-                                                      4H-1,2,6-thiadiazin-4-one                                         7           3-chloro-5-heptylthio-4H-                                                     1,2,6-thiadiazin-4-one                                            8           3-chloro-5-(phenylmethylthio)-                                                4H-1,2,6-thiadiazin-4-one                                         9           3-chloro-5-(cyclohexylthio)-                                                  4H-1,2,6-thiadiazin-4-one                                         10          3-chloro-5-(4-methylphenylthio)-                                              4H-1,2,6-thiadiazin-4-one                                         11          3-chloro-5-(4-methoxyphenylthio)-                                             4H-1,2,6-thiadiazin-4-one                                         12          3-chloro-5-(4-chlorophenylthio)-                                              4H-1,2,6-thiadiazin-4-one                                         13          3-chloro-5-(4-acetamido-                                                      phenylthio)-4H-1,2,6-thia-                                                    diazin-4-one                                                      14          3-chloro-5-(4-nitrophenylthio)-                                               4H-1,2,6-thiadiazin-4-one                                         15          3-chloro-5-(2,4,5-trichloro-                                                  phenylthio)-4H-1,2,6-thiadiazin-                                              4-one                                                             ______________________________________                                    

The following examples demonstrate the practice of the presentinvention. The test organisms used in these examples, together with anidentifying codes which are in the tables to identify each organism, areas follows:

As = alternaria solani

Bc = botrytis cinerea

Cc = cladosporium cucumerinum

Ep = erysiphe polygoni

Fs = fusarium solani

Ho = helminthosporium oryzae

Po = pyricularia oryzae

Pu = pythium ultimum

Rs = rhizoctonia solani

Sf = sclerotinia fructicola

Up = uromyces phaseoli

Pi = phytophthora infestans

Vi = venturia inaequalis

EXAMPLE III Spore Germination Tests

The test chemical was dissolved or suspended in acetone in an amountsuch that 0.8 ml of the resulting suspension or solution, mixed with 40ml water agar produced a water agar solution containing 40, 10, 2.5 and1 ppm of test chemical. The resulting agar solution, at 50° C, was thendivided equally between two sterile petri dishes, each having fourseparated quadrants, and allowed to solidify. Three quadrants of eachdish were flooded with 0.1 ml of a spore suspension in sterile water.Spores of two pathogens, Erysiphe polygoni and Uromyes phaseoli, frominfected plant leaves, were brushed on the remaining two quadrants. Thetests were then incubated 48 hours, at 24° C.

Readings were then taken and the percentage of germinated sporescalculated. From this percentage, a spore germination rating wasassigned as follows:

    ______________________________________                                        % Germination      Rating                                                     ______________________________________                                         0 - 10            0                                                          10 - 40            1                                                          40 - 60            2                                                          60 - 80            3                                                           80 - 100          4                                                          ______________________________________                                    

Table I reports the inhibitory effect of these test compounds on sporegermination and demonstrates improvement over benomyl which was used asa standard for comparison. In Table I, the lower the numeral used as arating, the more effective the compound.

EXAMPLE IV Mycelial Growth Tests

Aliquots of previously prepared solutions of active ingredient inacetone were added to tubes containing 20 ml of sterile, melted potatodextrose agar that had been cooled to 50° C to provide mixtures of 40,20, 10, 5 and 2.5 ppm. The tubes were shaken to ensure thorough mixingof the chemical with the agar, and the mixture poured into petri disheshaving 4 quadrants to solidify. Each quadrant was inoculated with a 4 mmdiameter disc of agar containing mycelium of the test fungi andincubated at 25° C for 72-144 hours during which the samples werealternately exposed to light for 12 hours and to darkness for 12 hours.Growth was measured at the end of the incubation period by measuring thediameter of each fungus colony. Two measurements of the diameter,perpendicular to each other, were taken and the values averaged. Dataare reported as percent inhibition (%I) by the following formula:##EQU1## Captan and chlorothalonil were used as standards forcomparison. The results reported in Table II indicate that the testcompounds were generally more active than the standards.

EXAMPLE V

The compounds of this invention were tested for corp disease control todetermine the basic types of antifungal activity they exhibit.

A. Foliar Protective Activity

The foliage of a tomato plant in the four leaf stage and a pinto bean inthe primary leaf stage was sprayed with the test chemicals at aconcentration of 150 ppm on a weight/volume basis, and the plant allowedto dry overnight.

Sporangia of Phytophthora infestans (late blight fungus) were harvestedfrom cultures grown on lima bean agar for 10 to 14 days. A watersuspension of sporangia (2 × 10⁵ sporangia/ml) was incubated at 12° Cfor two hours in order to provide a zoospore suspension. Spores ofUromyces phaseoli (bean rust fungus) were collected from diseased plantsand a 2% spore powder mixture prepared using ABB Pyrax talc as adiluent.

The tomato plants were inoculated in a spray hood with the zoosporesuspension, then immediately incubated in a humidity chamber at 100%relative humidity at 18-20° C for four to five days. The bean plantswere inoculated by dusting the spore powder onto the leaves. This wasaccomplished by placing the spore powder in a cheesecloth bag andshaking the bag over the leaves. The inoculated plants were placed inthe humidity chamber at 100% relative humidity and 21° C for 24 hoursand then placed in the greenhouse for four to six days until diseasesymptoms developed.

The percent disease control was then determined by comparing the diseaseincidence in treated plants and untreated check plants. Results reportedin Table III demonstrate the efficacy of the compounds tested inpreventing tomato late blight and bean rust when applied to foliage ofuninfected plants at 150 ppm prior to disease infestation.

B. Foliar Curative Tests

In the curative tests the plants were inoculated with the appropriatepathogen 24 hours before chemical treatment. The following host-parasitecombinations were used:

    ______________________________________                                        PLANT        FUNGUS          DISEASE                                          ______________________________________                                        Phaseolus vulgaris L.                                                                      Uromyces phaseoli Link                                                                        bean rust                                        Phaseolus vulgaris L.                                                                      Erysiphe polygoni DC                                                                          bean powdery                                                                  mildew                                           Beta vulgaris                                                                              Cercospora beticola                                                                           sugar beet                                                                    leaf spot                                        Oryzae sativa L.                                                                           Pyricularia oryzae                                                                            rice blast                                       ______________________________________                                    

Spores of bean rust and bean powdery mildew were obtained from diseasedplants. Spores of Cercospora beticola and Pyricularia oryzae wereharvested from petri dish cultures. C. beticola was grown on potatodextrose agar and P. oryzae on a glucose yeast extract medium. Thecultures were grown at 25° C for 10 days.

Beans (c. v. `Pinto`) were inoculated with rust as described in ExampleIV-A. Beans (c. v. `Bountiful`) at primary leaf stage were inoculatedwith powdery mildew by shaking diseased leaves over the test plants,thereby creating a spore deposit on leaves of the tests plants. Sugarbeets and rice were inoculated by spraying a water suspension of sporesof the appropriate pathogen on the foliage.

All of the plants except those inoculated with bean powdery mildew wereincubated in the moisture chamber (21° C) for 24 hours. The bean powderymildew inoculated plants were incubated in the greenhouse.

The test chemical was sprayed on the foliage of the plants at 150 ppm 24hours after inoculation. The bean and rice plants were removed from themoisture chamber and allowed to dry before chemical treatment. Aftertreatment the plants were incubated in the greenhouse for 6-10 days. Thesugar beets were sprayed while still wet, after which they wereimmediately returned to the moisture chamber for two days and then tothe greenhouse for 10-14 days.

The results tabulated in Table III demonstrate curative activity whenthe compounds were applied after infection of the plant.

C. Soil/Seed Treatment

Containers having a volume of about 0.25 l. were 2/3 filled with topsoiland 25 cucumber c.v. Straight Eight seeds deposited on the soil surfaceof each pot. A suspension containing 150 ppm of the test chemical waspoured over the seeds and into the soil in sufficient quantity toprovide 3.75 to 3.8 mg active ingredient per pot.

Fungi used in this test were Pythium ultimum and Rhizoctonia solani.These fungi were each grown on potato dextrose agar for three to sixdays. The agar plus mycelium was then minced in a blender with water and10 ml of the resulting slurry of minced mycelium poured over the seeds.

Following inoculation approximately 15 mm of topsoil was spread over theseeds, the container capped and incubated at 4° C in darkness for threedays, then transferred to a greenhouse (27° C) for 10-14 days, at whichtime stand counts were made. Captan was used as a standard forcomparison. Based on stand counts an Efficacy Index was calculated foreach test chemical as follows: ##EQU2##

The results, set forth in Table III, show that several of the compoundstested were considerably more effective than captan while others wereless effective for cucumber damping-off complex.

In a similar manner the soil around a bean seedling was drenched with asufficient amount of 150 ppm suspension of test chemical to provide 3.8mg active per pot. Twenty-four hours later the soil was inoculated witha suspension of minced mycelium of Fusarium solani. The inoculatedplants were then placed in a greenhouse, evaluated after fourteen days,and percent control of root rot damage calculated. The results, reportedin Table III, indicate that only a few of the compounds were effectiveunder the test conditions in treating bean root rot, but these provideda high degree of control.

                  TABLE I                                                         ______________________________________                                        Results of In Vitro Spore Germination Inhibition Testing                      CPD    Conc.   Spore Germination Rating                                       No.    ppm     BC     PO   VI  AS   CC   PI  EP   UP                          ______________________________________                                        3      10      0      0    0   0    0    0   0    0                                  2.5     0      0    0   1    0    2   3    0                                  1.0     0      0    0   3    0    4   4    0                           4      40      0      0    0   0    0    2   0    0                                  10      0      0    0   0    0    3   0    0                                  2.5     0      0    0   0    0    3   0    0                                  1.0     0      0    0   3    0    4   1    0                           5      40      0      0    0   0    0    1   0    0                                  10      0      0    0   0    0    1   0    0                                  2.5     0      0    0   2    0    2   0    0                                  1.0     0      0    0   4    0    2   0    0                           7      40      1*     0    0   1    0    0   0    0                                  10      2*     0    0   4    0    0   0    0                                  2.5     2      0    2   4    0    2   0    0                                  1.0     3      0    3   4    1    4   0    4                           8      40      0      0    0   0    0    0   0    0                                  10      1*     0    0   3    0    0   0    0                                  2.5     1*     1    0   3    0    0   0    0                                  1.0     1*     0    0   3    0    0   1    0                           9      40      0      0    0   0    0    0   0    0                                  10      0      0    0   1*   0    0   0    0                                  2.5     1*     0    0   3*   0    3   0    0                                  1.0     1*     0    0   4    0    4   2    0                           10     10      0      0    0   0    0    0   0    0                                  2.5     0      0    0   1    0    0   0    0                                  1.0     0      0    0   4    0    0   0    0                           11     40      0      0    0   0    0    0   0    0                                  10      0      1    0   0    0    0   1    0                                  2.5     0      0    0   3    0    2   3    0                                  1.0     0      2    0   4    0    4   4    1                           12     40      0      0    0   0    0    0   0    0                                  10      0      0    1*  0    0    1   0    0                                  2.5     0      0    1*  0    0    1   0    0                                  1.0     0      0    1*  0    0    1   0    0                           13     40      0      0    0   0    0    0   1    0                                  10      0      0    0   0    0    0   4    0                                  2.5     0      0    0   3    0    1   4    0                                  1.0     1      3    0   4    0    4   4    1                           14     40      0      0    0   0    0    0   0    0                                  10      0      0    0   0    0    0   0    0                                  2.5     0      0    0   0    0    1   1    0                                  1.0     0      0    0   0    0    1   1    0                           15     40      0      0    0   0    0    0   0    0                                  10      0      0    0   0    0    0   0    0                                  2.5     0      0    1*  0    0    1   0    0                                  1.0     0      0    1   3    0    1   1    1                           Benomyl                                                                              40      4*     0    0   4    0    1   0    0                                  10      4*     3*   0   4    3*   0   0    1*                                 1.0     4*     4*   3   4    4*   2   2    4                           ______________________________________                                         *Abortive Germ Tubes                                                     

                                      TABLE II                                    __________________________________________________________________________    Results of In Vitro Mycelial Growth Inhibition Evaluation                     Percent Fungus Growth Inhibitor                                               CPD Conc.                                                                     No. ppm.                                                                              AS  FS  SF  PO  PU  RS  HO  CC                                        __________________________________________________________________________    1   40  --  100 --  --  100 100 100 --                                            20  --  100 --  --  100 84  100 --                                            10  --  56  --  --  24  64  77  --                                            5   --  93  --  --  0   42  73  --                                        2   40  --  100 --  --  100 100 100 --                                            20  --  100 --  --  100 78  85  --                                            10  --  100 --  --  38  56  73  --                                            5   --  81  --  --  0   20  85  --                                        3   40  100 100 100 100 100 100 100 100                                           20  90  100 100 93  100 100 100 71                                            10  81  100 100 63  100 89  89  42                                            5   81  42  100 30  60  73  74  33                                        4   40  35  100 100 100 100 100 100 100                                           20  87  100 100 47  100 100 100 54                                            10  55  63  100 40  100 87  89  42                                            5   48  74  100 20  84  82  79  33                                        5   40  61  79  100 47  100 87  89  54                                            20  48  47  100 33  100 84  100 50                                            10  68  74  88  30  89  84  79  25                                            5   55  58  100 13  69  64  58  33                                        6   40  --  100 --  --  100 82  100 --                                            20  --  100 --  --  89  69  100 --                                            10  --  100 --  --  0   42  50  --                                            5   --  100 --  --  0   20  46  --                                        7   40  16  58  39  13  49  64  68  29                                            20  29  58  33  13  0   33  58  33                                            10  16  58  21  13  0   31  49  13                                            5   16  37  21  13  0   38  21  13                                        8   40  48  33  47  23  0   47  41  8                                             20  24  5   23  29  0   0   24  0                                             10  24  14  20  3   0   0   18  17                                            5   0   24  20  3   0   0   6   0                                         9   40  55  79  55  30  100 80  100 42                                            20  35  74  88  20  89  87  79  38                                            10  39  63  100 30  64  64  78  42                                            5   48  --  67  23  --  --  --  38                                        10  40  62  62  83  8   76  64  100 33                                            20  29  52  73  10  42  60  41  25                                            10  48  62  87  8   47  56  76  33                                            5   24  48  73  11  0   31  35  33                                        11  40  77  100 100 73  100 78  100 63                                            20  55  74  100 93  100 78  100 67                                            10  48  84  94  50  100 82  58  42                                            5   45  42  76  53  100 69  68  17                                        12  40  38  48  67  74  36  64  47  8                                             20  19  33  57  68  13  49  76  8                                             10  48  24  77  74  0   58  47  17                                            5   38  43  70  71  4   58  47  17                                        13  40  86  52  90  94  100 69  88  8                                             20  81  48  90  90  78  56  65  8                                             10  57  33  87  52  52  73  53  17                                            5   43  29  67  58  51  46  41  0                                         14  40  24  29  40  65  16  53  17  33                                            20  24  24  63  45  0   24  41  0                                             10  0   23  53  48  0   22  65  0                                             5   0   24  50  35  0   20  18  0                                         15  40  57  48  67  65  87  69  76  25                                            20  52  71  60  61  100 78  100 17                                            10  5   52  50  61  100 67  100 8                                             5   0   48  23  39  76  69  100 0                                         Captan                                                                            40  --  44  --  --  0   0   65  --                                            20  --  48  --  --  0   0   62  --                                            10  --  33  --  --  0   0   46  --                                            5   --  19  --  --  0   0   18  --                                        Chlor-                                                                            40  75  88  82  48  100 73  95  96                                        thal-                                                                             20  38  76  76  41  100 53  73  71                                        onil                                                                              10  50  41  70  15  31  40  59  63                                            5   44  41  67  26  0   31  50  63                                        __________________________________________________________________________

                                      TABLE III                                   __________________________________________________________________________    RESULTS OF FUNGICIDE PRIMARY SCREEN TESTING                                                                  Efficacy                                       Percent Disease Control        Index                                          Foliar      Curative       Seed/Soil                                                              Sugar      Cucumber                                          Tomato      Bean Beet   Bean                                                                              Damping-                                       CPD                                                                              Late Bean                                                                              Bean                                                                             Powdery                                                                            Leaf                                                                              Rice                                                                             Root                                                                              off                                            No.                                                                              Blight                                                                             Rust                                                                              Rust                                                                             Mildew                                                                             Spot                                                                              Blast                                                                            Rot Complex                                        __________________________________________________________________________    1  0    0   0  50   0   0  0   132                                            2  0    0   0  50   0   0  100 126                                            3  0    0   0  0    0   0  0   99                                             4  0    0   0  0    0   0  0   105                                            6  0    0   0  100  50  0  50  105 (a)                                        7  0    0   0  0    0   0  0   0                                              8  100  0   0  90   95  0  0   0                                              10 98   0   0  0    0   0  0   0                                              11 0    90  0  0    0   0  0   83                                             12 0    50  0  0    0   0  DP(b)                                                                             0                                              13 0    100 0  0    0   0  90  53                                             14 95   100 0  0    0   0  0   76                                             15 0    DP(b)                                                                             0  0    0   0  90  0                                              __________________________________________________________________________     (a)Slight phylotoxicity                                                       (b)DP = Dead Plant                                                       

We claim:
 1. A method for control of fungal disease of plants comprisingapplying to the locus where control is desired an effective fungistaticor fungicidal amount of a compound having the formula: ##STR4## whereinX is alkylthio having 1 to 8 carbon atoms, phenylthio, phenyl(lower)-alkylthio, cycloalkylthio having 5 to 7 ring carbon atoms orsubstituted phenylthio having the formula: ##STR5## wherein each R isindependently lower alkyl, lower alkoxyl, lower acylamino having 1 to 4carbon atoms, lower alkoxycarbonyl, nitro, cyano or halogen and n is anintegar having a value of 1 to 3 inclusive, with the proviso that when Ris lower alkyl or halogen n maybe an integer having a value of 1 to 5inclusive.
 2. The method of claim 1 wherein said compound is applied inadmixture with an agriculturally acceptable carrier and a compatiblesurface active agent.
 3. The method of claim 2 wherein said compound isapplied to seeds, plant foilage or soil in which plants are planted orare to be planted.
 4. An antifungal composition comprising an effectivefungistatic or fungicidal amount of a compound of the formula: ##STR6##wherein X is alkylthio having 1 to 8 carbon atoms, phenylthio, phenyl(lower)-alkylthio, cycloalkylthio having 5 to 7 ring carbon atoms orsubstituted phenylthio having the formula: ##STR7## wherein each R isindependently lower alkyl, lower alkoxyl, lower acylamino having 1 to 4carbon atoms, lower alkoxycarbonyl, nitro, cyano or halogen and n is aninteger having a value of 1 to 3 inclusive, with the proviso that when Ris lower alkyl or halogen n may be an integer having a value of 1 to 5inclusive, in admixture with an agriculturally acceptable carrier and acompatible surface active agent.
 5. The antifungal composition of claim4 wherein X is other than methylthio or phenylthio.